1. Field of the Invention
The present invention relates to a pipe joint of a quick connector type suitable for connecting pipes of, for example, a radiator, a heater unit, a fuel supply system or the like of an automobile, particularly relates to a pipe joint having a rotation preventing unit.
2. Description of the Related Art
There is used a pipe joint of a quick connector type in connecting pipes of, for example, a radiator, a heater unit, a fuel supply system or the like of an automobile. Generally, the pipe joint is provided with a socket substantially in a tubular shape attached to one pipe end, a plug substantially in a tubular shape attached to other pipe end and inserted into the socket, a retaining unit for preventing the plug from being drawn out from the socket, a seal ring arranged at an inner periphery of the socket for sealing the inner periphery of the socket and an outer periphery of the plug, and a hold ring arranged at the inner periphery of the socket for hampering the seal ring from being moved.
Meanwhile, depending on use thereof, there is a case in which not only a plug needs to be prevented from being drawn out from a socket but also the plug needs to be restricted from being rotated. There is known such a pipe joint in which, for example, an outer periphery of a plug is formed with a projected portion, and an inner periphery of a socket is formed with a guide groove along an axial direction inserted with the projected portion.
Meanwhile, JP-A-2002-276878, discloses a piping joint characterized in a piping joint including a male joint member having a spool portion, a female joint member, a retainer inserted from an window portion opened to a housing of the female joint member from a direction orthogonal to an axial direction for coupling the male joint portion and the female joint portion, and an O ring mounted to inside of the female joint member, in which the retainer is provided with a holding portion engaged with the spool portion of the male joint member for holding a distal end of the male joint member to be prevented from being drawn, and a rotation preventing unit for preventing the female joint member and the male joint member from being rotated relatively is constituted by cooperating the male joint member and the holding portion of the retainer.
Further, it is described that the holding portion includes a rib formed integrally with the retainer and bent in a U-like shape by following an outer peripheral face of the male joint member, and the rotation preventing unit includes a noncircular portion formed at the male joint member and having a noncircular cross-sectional face, and a fixing portion provided at the rib for fixing to be able to restrain the noncircular portion from being rotated.
However, according to the pipe joint of the background art in which the outer periphery of the plug is formed with the projected portion and the inner periphery of the socket is formed with the guide groove along the axial direction inserted with the projected portion, when, for example, a side of the plug is constituted by a metal pipe or the like, it is difficult to form the projected portion at the outer periphery and fabrication thereof is difficult.
According to the above-described pipe joint of JP-A-2002-276878, rotation thereof is restricted by providing the noncircular portion (for example, a flat portion) having the noncircular cross-sectional shape at the male joint member and providing the fixing portion engaged with the noncircular portion at the retainer, there poses a problem that a flow path diameter of the male joint member (plug) is narrowed at the noncircular portion, rotation is not restricted unless the retainer is pressed down, further, the retainer cannot be pressed down unless the male joint member constitutes a predetermined angle relative to the female joint member.